Oakham trainer Mick Appleby criticised the decision to allow Tuesday's evening meeting at Leicester to go ahead after withdrawing his three intended runners due to safety concerns.
The fixture got the green following morning consultation between local health authorities and the British Horseracing Authority.
It had been put in doubt as the city has recently been placed back under lockdown measures.
Due to a spike in Covid-19 cases in the area, Health Secretary Matt Hancock announced on Monday evening that all non-essential businesses would have to close again, with schools also closing from Thursday.
The planned nationwide lifting of restrictions from July 4 will have to stay in place in Leicester until July 18 at the earliest.
The city has seen almost 1,000 new cases in the previous fortnight.
Appleby, whose stables are just 20 miles from the racecourse at Oadby, fancied his chances of a winner but felt it was not "worth the risk".
"Personally I don't think the meeting should have been allowed to go ahead," he said.
"You don't know who has been at the racecourse in the last few weeks, working there and so forth. I don't think it's safe.
"The owners have agreed. I'd have had two favourites there and probably two winners. What would happen in a couple of days if someone who attends the meeting tests positive (for coronavirus)? Your yard would end up going into lockdown.
"I just don't think it's worth the risk. It would have made common sense to call the meeting off. It's not doing racing any favours whatsoever."
Fellow trainers Alan King and Graeme McPherson also withdrew their horses for similar reasons.
The BHA underlined the meeting had been given the relevant approvals to take place, while also emphasising the strict protocols which the limited personnel on course must adhere to.
A statement said: "Local authorities confirmed on Tuesday morning that, as racecourses are a place of work, and strict safety criteria are in place, today's fixture at Leicester racecourse has been given permission to go ahead.
"The fixture is being held behind closed doors. Only essential personnel are permitted to work at racing fixtures at present, and our guidelines require attendees to have little or no contact with the local community. Attendees are expected go straight to and from the venue.
"The small handful of people attending who do live locally are going to work after rigorous medical screening and into an environment which is more controlled than most other businesses or day-to-day activities. Every attendee undergoes a stringent three-stage medical screening process. Strict social distancing measures are in place.
"The health of participants and the public was uppermost in determining the procedures we have put in place for all race meetings."
The track's general manager David Maykels explained the situation with the stalls handlers only came to light late in the day.
He told Racing TV: "I think out of a team of 12, four were prepared to come to Leicester even though, I would say, they are probably the safest group of people on the course because they come straight through, they are in the centre of the course and they are segregated from everybody else here.
"The only real argument I guess anyone can have is the local people (staff) here could be the people who contaminate others, but we're all checked on a regular basis so it's disappointing really that it happened so late. It would have been nice to know people didn't want to come earlier on."
Leicester is due to race again next week, but Maykels believes that fixture may need to be reviewed given the current situation.
He added: "I think we need to have a conversation after this meeting and see whether it's possible to maybe reschedule that - I don't know, we'll have to see.
"If this situation carries on locally, the decision will be made by the BHA as to whether we race again next week. We want to race, so if there's any risk or any possibility we could have a problem, we need to talk about how we could alleviate that."
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